Win all ten matches in Normal mode under the Normal or better difficulty setting without any continues. A bonus eleventh match will begin after the credits end.
Win the bonus eleventh match under the Normal or better difficulty setting to unlock a fourth color for the character played.
OverDriven CPU opponent:
Win the bonus eleventh match under the Hard or Nightmare difficulty setting to unlock the OverDriven version of the opponent that was defeated. Press C when selecting that character as an opponent in Vs. CPU mode. This can also be done in Watch mode for both characters.